Datediff in class AXAPTA

i have a script such as below :

public void processReport()
{
    QueryRun            qr;
    PurchReqTable       purchReqTable;
    PurchReqLine        purchReqLine;
    PurchLine           purchLine,lastPurchLine;
    InventTrans         inventTrans;
    InventTransOrigin   inventTransOrigin;


    MK_PurchReqReportContract   contract = this.parmDataContract() as MK_PurchReqReportContract;
    utcDateTime         fromDate = DateTimeUtil::newDateTime(contract.parmFromDate(),0,DateTimeUtil::getCompanyTimeZone());
    utcDateTime         toDate = DateTimeUtil::newDateTime(contract.parmToDate(),DateTimeUtil::time(DateTimeUtil::maxValue()),DateTimeUtil::getCompanyTimeZone());

    qr = new QueryRun(this.parmQuery());
    qr.query().dataSourceTable(tableNum(PurchReqTable)).addRange(fieldNum(PurchReqTable,CreatedDateTime))
    .value(SysQuery::range(fromDate,toDate));

    while (qr.next())
    {
        purchReqTable = qr.get(tableNum(PurchReqTable));

        tmpPurchReqReport.PurchReqId                = purchReqTable.PurchReqId;
        tmpPurchReqReport.PurchReqName              = purchReqTable.PurchReqName;

        while select purchReqLine
               where purchReqLine.PurchReqTable == purchReqTable.RecId
        {
            purchLine = purchReqLine.purchLine();

            tmpPurchReqReport.PurchReqId                = purchReqTable.PurchReqId;
            tmpPurchReqReport.PurchReqName              = purchReqTable.PurchReqName;
            tmpPurchReqReport.PurchReqDate              = DateTimeUtil::date(purchReqTable.createdDateTime);
            tmpPurchReqReport.SubmittedDateTime         = purchReqTable.SubmittedDateTime;
            tmpPurchReqReport.Requester                 = purchReqLine.requisitionerName();
            tmpPurchReqReport.Preparer                  = purchReqTable.originatorName();
            tmpPurchReqReport.ItemDescription           = purchReqLine.MK_Description;
            tmpPurchReqReport.ItemId                    = purchReqLine.ItemId;
            tmpPurchReqReport.ItemName                  = purchReqLine.itemName();
            tmpPurchReqReport.PurchId                   = purchReqLine.PurchId;
            tmpPurchReqReport.PurchQty                  = purchReqLine.PurchQty;
            tmpPurchReqReport.PurchUnit                 = purchReqLine.unitOfMeasureSymbolById();
            tmpPurchReqReport.PurchPrice                = purchReqLine.PurchPrice;
            tmpPurchReqReport.CurrencyCode              = purchReqLine.CurrencyCode;
            tmpPurchReqReport.LineAmount                = purchReqLine.LineAmount;
            tmpPurchReqReport.VendAccount               = purchReqLine.VendAccount;
            tmpPurchReqReport.VendName                  = purchReqLine.vendName();
            tmpPurchReqReport.LeadTimeStd               = purchReqLine.inventTable().MK_LeadTime;

            tmpPurchReqReport.CostCenter                = MK_DimensionClass::getValueFromDefaultDimension(purchReqLine.DefaultDimension,"CostCenter");
            tmpPurchReqReport.Department                = MK_DimensionClass::getValueFromDefaultDimension(purchReqLine.DefaultDimension,"Department");
            tmpPurchReqReport.Purpose                   = MK_DimensionClass::getValueFromDefaultDimension(purchReqLine.DefaultDimension,"Purpose");
            tmpPurchReqReport.Spec                      = MK_DimensionClass::getValueFromDefaultDimension(purchReqLine.DefaultDimension,"Spec");
            tmpPurchReqReport.Spec1                     = MK_DimensionClass::getValueFromDefaultDimension(purchReqLine.DefaultDimension,"Spec1");

            this.setFieldManager(purchReqTable);
            this.setFieldSeniorManager(purchReqTable);
            this.setFieldRFQ(purchReqTable);
            this.setFieldDirector(purchReqTable);

i want tmpPurchReqReport.LeadTimeStd is today - tmpPurchReqReport.PurchReqDate.

any solution for me?

thanks before..